Image forming apparatus

ABSTRACT

An image forming apparatus includes an image forming device which forms an image on a recording medium and an image scanning device which transmits scanned image data to the image forming device. The image forming device includes a receiver, a first image forming unit, a second image forming unit, and a controller. The receiver receives at least one of external image data transmitted from an external device and the scanned image data as input image data. The first image forming unit forms a developer image based on the input image data on the recording medium. The second image forming unit forms a mark image on the recording medium. The controller determines whether to make the second image forming unit form the mark image or not depending on a type of a transmission source of the input image data.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image forming apparatus having afunction of forming a mark image with luminescent developer on arecording medium.

2. Description of the Related Art

Conventionally, there is proposed an image forming apparatus that printsa composite image of an image (tag) regarding copy restriction onprinted matter and an image based on input image data on a recordingmedium (see Patent Reference 1: Japanese Patent Application PublicationNo. 2008-268588, for example)

SUMMARY OF THE INVENTION

However, it is difficult to distinguish the source of the transmissionof the input image data on the basis of the image formed by theconventional image forming apparatus. For example, it is difficult todistinguish based on printed matter itself whether an image on theprinted matter is an image based on input image data whose transmissionsource is a client personal computer (PC), an image based on input imagedata whose transmission source is a facsimile machine, or an image basedon scanned image data generated by optically scanning a document with animage scanning device.

An object of the present invention is to provide an image formingapparatus that makes it possible to identify the type of thetransmission source of the image printed on the recording medium.

MEANS FOR SOLVING THE PROBLEM

An image forming apparatus according to an aspect of the presentinvention includes an image forming device which forms an image on arecording medium and an image scanning device which transmits scannedimage data generated by optically scanning an image to the image formingdevice. The image forming device includes a receiver, a first imageforming unit, a second image forming unit, and a controller. Thereceiver receives at least one of external image data transmitted froman external device and the scanned image data transmitted from the imagescanning device as input image data. The first image forming unit formsa developer image based on the input image data on the recording medium.The second image forming unit forms a mark image on the recording mediumwith luminescent developer containing a luminescent material. Thecontroller determines whether to make the second image forming unit formthe mark image or not depending on a type of a transmission source ofthe input image data.

According to the present invention, the type of the transmission sourceof the image printed on the recording medium can be identified.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view (partially longitudinal sectional view)schematically showing the configuration of an image forming apparatusaccording to an embodiment of the present invention.

FIG. 2 is a block diagram schematically showing the configuration of acontrol system of the image forming apparatus according to the firstembodiment.

FIG. 3 is a flowchart showing an example of the operation of the imageforming apparatus according to the first embodiment.

FIG. 4 is a diagram showing setting information stored in a storage unitof an image forming device of the image forming apparatus according tothe first embodiment in a table format.

FIG. 5 is a diagram showing an example of a composite image of an imageformed with normal toner and an image formed with a luminescent toner.

FIG. 6 is a flowchart showing an example of the operation of an imageforming apparatus according to a second embodiment.

FIGS. 7A and 7B are diagrams each showing an example of a mark imageformed with the luminescent toner printed in a printable region of asheet of paper.

FIGS. 8A and 8B are diagrams each showing an example of a mark imageformed with the luminescent toner printed in a marginal region of thesheet of paper other than the printable region.

MODE FOR CARRYING OUT THE INVENTION <<1>> First Embodiment <<1-1>> ImageForming Apparatus

FIG. 1 is a front view (partially longitudinal sectional view)schematically showing the configuration of an image forming apparatus 1according to an embodiment of the present invention. As shown in FIG. 1,the image forming apparatus 1 according to a first embodiment includesan image forming device (referred to also as a “printing unit”) 100which forms an image on a sheet of paper (also referred to as a sheet)as a recording medium and an image scanning device (referred to also asa “scanner unit”) 200 which generates scanner data Ds as scanned imagedata by optically scanning an image and transmits the scanner data Ds tothe image forming device 100. The image scanning device 200 is supportedon the upper side of the image forming device 100 by support members 101provided on a housing 4 of the image forming device 100. However, thepositional relationship between the image forming device 100 and theimage scanning device 200 is not limited to the example shown in FIG. 1.Further, the image forming device 100 and the image scanning device 200do not necessarily have to be provided as units separate from eachother. The image forming device 100 and the image scanning device 200may be provided in one housing.

In the present embodiment, a process of forming the image (i.e., adeveloper image) on the sheet with developer (developing agent) such astoner and ink on the basis of image data (input image data) transmittedfrom the image scanning device 200 or an external device is referred toas “developing”.

As shown in FIG. 1, the image forming device 100 includes first processunits 2Y, 2M, 2C and 2K as first image forming units, a second processunit 2V as a second image forming unit and an intermediate transfer belt3.

The first process units 2Y, 2M, 2C and 2K respectively form a tonerimage as the developer image of yellow (Y) color, a toner image as thedeveloper image of magenta (M) color, a toner image as the developerimage of cyan (C) color, and a toner image as the developer image ofblack (B) color on the intermediate transfer belt 3 by means ofelectrophotography.

The second process unit 2V forms a toner image as the developer imagewith luminescent toner as luminescent developer (V) (e.g., a mark image)on the intermediate transfer belt 3 by means of electrophotography.

The first process units 2Y, 2M, 2C and 2K can be identical in structurewith each other except that the colors of the toner as the developerused for the units differ from each other. The second process unit 2Vcan be identical in structure with the first process units 2Y, 2M, 2Cand 2K except that the type of the toner as the developer used for theunit is different.

The second process unit 2V and the first process units 2Y, 2M, 2C and 2Kare arranged in this order (tandem arrangement) in the conveyancedirection (D1 direction) of the intermediate transfer belt 3. While theimage forming apparatus 1 of the intermediate transfer type employingthe intermediate transfer belt 3 is illustrated in FIG. 1, the presentinvention is applicable also to image forming apparatuses including nointermediate transfer belt and making the first process units 2Y, 2M, 2Cand 2K and the second process unit 2V directly transfer toner imagesonto the recording medium. Further, the order of arrangement of thesecond process unit 2V and the first process units 2Y, 2M, 2C and 2K isnot limited to the example shown in FIG. 1. Furthermore, while fourfirst process units 2Y, 2M, 2C and 2K are shown in FIG. 1, the number offirst process units can be other than four as long as the number is oneor more (at least one).

The first process units 2Y, 2M, 2C and 2K respectively includephotosensitive drums 11Y, 11M, 11C and 11K as image carriers, chargingrollers 12Y, 12M, 12C and 12K as charging units, LED (Light EmittingDiode) heads 13Y, 13M, 13C and 13K as exposure units, developmentrollers 14Y, 14M, 14C and 14K as developer carriers, development blades15Y, 15M, 15C and 15K as developer regulation members, supply rollers16Y, 16M, 16C and 16K as developer supply units, cleaning blades 17Y,17M, 17C and 17K as developer removal members, and toner cartridges 18Y,18M, 18C and 18K as developer supply units.

The second process unit 2V includes a photosensitive drum 11V as animage carrier, a charging roller 12V as a charging unit, an LED head 13Vas an exposure unit, a development roller 14V as a developer carrier, adevelopment blade 15V as a developer regulation member, a supply roller16V as a developer supply unit, a cleaning blade 17V as a developerremoval member, and a toner cartridge 18V as a developer supply unit.Incidentally, the second process unit 2V and the first process units 2Y,2M, 2C and 2K will be referred to also as “process units 2V, 2Y, 2M, 2Cand 2K”.

The photosensitive drums 11V, 11Y, 11M, 11C, and 11K are rotatablysupported in the corresponding process units 2V, 2Y, 2M, 2C, and 2Krespectively. The charging rollers 12V, 12Y, 12M, 12C, and 12K uniformlycharge the surface of the corresponding photosensitive drums 11V, 11Y,11M, 11C, and 11K by applying a predetermined voltage to thephotosensitive drums 11V, 11Y, 11M, 11C, and 11K respectively.

Each of the LED heads 13V, 13Y, 13M, 13C, and 13K has a plurality oflight-emitting devices (LEDs) arranged in a main scan direction(direction orthogonal to the sheet of FIG. 1 and orthogonal to the D1direction). Each of the LED heads 13Y, 13M, 13C, and 13K forms anelectrostatic latent image on the uniformly charged surface of thecorresponding photosensitive drums 11Y, 11M, 11C, and 11K by irradiatinglight based on input image data (data Di in FIG. 2 which will beexplained later) to the surface of the photosensitive drum 11Y, 11M,11C, and 11K respectively. The LED head 13V forms an electrostaticlatent image on the uniformly charged surface of the photosensitive drum11V by irradiating light based on mark image data (e.g., data stored ina storage unit 140 (memory) in FIG. 2 which will be explained later) tothe surface of the photosensitive drum 11V.

Each of the development rollers 14V, 14Y, 14M, 14C, and 14K forms atoner image by having a toner adhere to the electrostatic latent imageon the photosensitive drums 11V, 11Y, 11M, 11C, and 11K respectively.Each of the development blades 15V, 15Y, 15M, 15C, and 15K regulates thethickness of the toner supplied to the surface of the correspondingdevelopment rollers 14V, 14Y, 14M, 14C, and 14K and thereby forms a thinlayer of the toner, respectively. Each of the supply rollers 16V, 16Y,16M, 16C, and 16K makes contact with the corresponding developmentrollers 14V, 14Y, 14M, 14C, and 14K and supplies the toner from thecorresponding toner cartridges 18V, 18Y, 18M, 18C, and 18K to thedevelopment rollers 14V, 14Y, 14M, 14C, and 14K respectively. Each ofthe toner cartridges 18V, 18Y, 18M, 18C, and 18K stores the toner.

Each of the cleaning blades 17V, 17Y, 17M, 17C, and 17K wipes offfogging toner and transfer residual toner remaining on the surface ofthe corresponding photosensitive drums 11V, 11Y, 11M, 11C, and 11K andreversely transferred toner from the process units 2V, 2Y, 2M, 2C, and2K situated upstream of the intermediate transfer belt 3 in theconveyance direction, respectively.

The image forming device 100 includes primary transfer rollers 19V, 19Y,19M, 19C and 19K. The primary transfer rollers 19V, 19Y, 19M, 19C and19K are arranged to respectively face the photosensitive drums 11V, 11Y,11M, 11C and 11K across the intermediate transfer belt 3. Each of theprimary transfer rollers 19V, 19Y, 19M, 19C, and 19K presses theintermediate transfer belt 3 in cooperation with the correspondingphotosensitive drums 11V, 11Y, 11M, 11C, and 11K and thereby transfersthe toner image to the surface (outer circumferential surface) of theintermediate transfer belt 3, respectively.

The process units 2V, 2Y, 2M, 2C and 2K may be equipped with up/downsolenoids 20V, 20Y, 20M, 20C and 20K, respectively. Each of the up/downsolenoids 20V, 20Y, 20M, 20C, and 20K moves the corresponding processunits 2V, 2Y, 2M, 2C, and 2K (in the vertical direction in FIG. 1) sothat the photosensitive drums 11V, 11Y, 11M, 11C, and 11K of the processunits 2V, 2Y, 2M, 2C, and 2K contacts or separates from the intermediatetransfer belt 3, respectively. Each of the up/down solenoids 20V, 20Y.20M, 20C, and 20K carries out the switching between a contact state (usestate) in which the process units 2V, 2Y, 2M, 2C, and 2K is in contactwith the intermediate transfer belt 3 and a separate state (non-usestate) in which the process units 2V, 2Y, 2M, 2C, and 2K is separatedfrom the intermediate transfer belt 3, respectively.

The intermediate transfer belt 3 in an endless shape is formed of ahigh-resistance semiconductive plastic film, for example. Theintermediate transfer belt 3 is stretched at predetermined tension by adrive roller 21, a driven roller 22 and a secondary transfer counterroller 23. The drive roller 21 is rotated by a belt motor working as atransfer belt drive unit and carries (moves) the intermediate transferbelt 3 in the directions of arrows D1 and D2. The driven roller 22rotates according to the movement of the intermediate transfer belt 3. Atop part of the intermediate transfer belt 3 is stretched between thephotosensitive drums 11V, 11Y, 11M, 11C and 11K and the primary transferrollers 19V, 19Y, 19M, 19C and 19K. The intermediate transfer belt 3 ispressed by the primary transfer rollers 19V, 19Y, 19M, 19C and 19Kagainst the photosensitive drums 11V, 11Y, 11M, 11C and 11K. Parts wherethe intermediate transfer belt 3 and the photosensitive drums 11V, 11Y,11M, 11C and 11K are in contact with each other will be referred to as“primary transfer nip parts”. In the primary transfer nip parts, thetoner images on the photosensitive drums 11V, 11Y, 11M, 11C, and 11K aretransferred to the intermediate transfer belt 3 by applying apredetermined DC voltage from a primary transfer voltage generation unitto the primary transfer rollers 19V, 19Y, 19M, 19C, and 19Krespectively.

The image forming device 100 includes a sheet feed mechanism 5 whichsupplies sheets to a conveyance path 10. In the example of FIG. 1, thesheet feed mechanism 5 is provided under the process units 2V, 2Y, 2M,2C and 2K and the intermediate transfer belt 3. The sheet feed mechanism5 includes a sheet storage cassette 31 as a media cassette, a hoppingroller 32 as a sheet feed roller, a pinch roller 33 and a resist roller34 constituting a conveyance roller pair, a guide 35, and a sheet feedsensor 36. Sheets of paper as the recording medium are stacked andstored in the sheet storage cassette 31. The hopping roller 32 sends outeach sheet stored in the sheet storage cassette 31 to the pinch roller33 and the resist roller 34. The pinch roller 33 corrects a skew of thesheet when the sheet is skewed (fed obliquely). The resist roller 34sends out the sheet to a secondary transfer roller 24 arranged at aposition facing the secondary transfer counter roller 23 across theintermediate transfer belt 3. The guide 35 guides the sheet to thesecondary transfer roller 24. The sheet feed sensor 36 detects the sheetreaching a position between the pinch roller 33 and the resist roller34.

The image forming device 100 includes the secondary transfer roller 24and the secondary transfer counter roller 23. The secondary transferroller 24 rotates according to the movement of the intermediate transferbelt 3. The intermediate transfer belt 3 is pressed by the secondarytransfer roller 24 against the secondary transfer counter roller 23. Apart where the secondary transfer roller 24 and the intermediatetransfer belt 3 are in contact with each other will be referred to as a“secondary transfer nip part”. In the secondary transfer nip part, thetoner image (including the mark image) on the intermediate transfer belt3 is secondarily transferred to the sheet by applying a predetermined DCvoltage, supplied from a secondary transfer voltage generation unitcontrolled by a drive control section 123, to the secondary transferroller 24.

The image forming device 100 includes a fixing unit 6. In the example ofFIG. 1, the fixing unit 6 is arranged on the downstream side of thesecondary transfer nip part in the conveyance path 10. Further, theimage forming device 100 includes a secondary transfer ejection sensor25 arranged between the secondary transfer roller 24 and the fixing unit6. The secondary transfer ejection sensor 25 monitors the conveyancepath 10 to check for winding of the sheet around the secondary transferroller 24, separation of the sheet from the intermediate transfer belt3, and so on.

The fixing unit 6 includes a heat roller 41, a pressure roller 42, aheater 43 and a thermistor 44. The heat roller 41 is driven by a fixingunit drive section such as a heater motor. The pressure roller 42 isarranged so as to face the heat roller 41 across the conveyance path 10.The pressure roller 42 rotates according to the rotation of the heatroller 41 and presses against the heat roller 41. The heater 43 is ahalogen lamp or the like functioning as a heat source. The heater 43 isprovided inside the heat roller 41 and heats the heat roller 41. Thethermistor 44 is arranged in the vicinity of the heat roller 41 andmeasures the surface temperature of the heat roller 41. The fixing unit6 heats and fuses the toner on the sheet conveyed along the conveyancepath 10 between the heat roller 41 and the pressure roller 42 andthereby fixes the toner image on the sheet.

The image forming device 100 includes a fixation ejection sensor 26. Inthe example of FIG. 1, the fixation ejection sensor 26 is arranged onthe downstream side of the fixing unit 6 in the media conveyancedirection in the conveyance path 10. The fixation ejection sensor 26monitors the fixing unit 6 to check for a paper jam, winding of thesheet around the heat roller 41, and so on. in the fixing unit 6.

In the image forming device 100, a guide 27 for conveying the sheet to astacker 28 at the upper end part of the housing 4 is provided on thedownstream side of the fixation ejection sensor 26 in the mediaconveyance direction in the conveyance path 10. The sheet after beingprinted on is ejected into the stacker 28 through the guide 27.

Further, in the image forming device 100, a cleaning blade 51 forremoving secondary transfer residual toner remaining on the intermediatetransfer belt 3 without being transferred to the sheet in the secondarytransfer is arranged on the downstream side of the secondary transfernip part of the intermediate transfer belt 3 to face a cleaning bladecounter roller 52. The cleaning blade 51, which is made of a flexiblerubber material or a plastic material, scrapes off the secondarytransfer residual toner remaining on the intermediate transfer belt 3into a waste toner tank 53.

The image forming device 100 may include an environmental sensor 7 formeasuring the temperature and the humidity as environmental conditions.For example, before the start of the print operation, the image formingdevice 100 determines the process unit (process unit 2V, 2Y, 2M, 2C or2K) that should contact or separate from the intermediate transfer belt3 based on the temperature and the humidity measured by theenvironmental sensor 7, and carries out the switching between thecontact state and the separate state.

FIG. 2 is a block diagram schematically showing the configuration of acontrol system of the image forming apparatus 1 according to the firstembodiment. As shown in FIG. 2, the image scanning device 200 includes ascanner section 201 which generates the scanner data Ds as the scannedimage data by optically scanning the image of a document, a scannercontroller 202 (scanner control section) which controls the operation ofthe image scanning device 200, and a scanner transmission/receptionsection 203 (scanner transmitting-receiving section) as a transmissionunit for transmitting the scanner data Ds generated by the scannersection 201 to the image forming device 100. Further, the image scanningdevice 200 may include a status management section 204 (image formingdevice status management section) for managing the operating status ofthe image forming device 100 and an operation panel 205 as a userinterface.

As shown in FIG. 1, the scanner section 201 generally includes contactglass 206 as document table glass on which a document as the object ofthe scanning can be set, a line sensor 208 as an optical sensor foroptically scanning the image of the document on the contact glass 206,and a light source lamp 209 for illuminating the document. The scannersection 201 may include an auto-feeder (automatic document feeder: ADF)207 for moving the document. Further, the scanner section 201 mayinclude a movement mechanism for moving the line sensor 208 and thelight source lamp 209.

The operation panel 205 includes a display mechanism such as a liquidcrystal display device and a switch (operation buttons of the touchpanel type), for example. The operation panel 205 is operated by anoperator (user). Each sheet of the document as the object of thescanning can be set one by one on the contact glass 206. The auto-feeder207 successively extracts each sheet of the document set thereon andconveys the extracted sheet to a scannable position of the scannersection 201.

Further, as shown in FIG. 2, the image forming device 100 includes atransmission/reception section 110 (receiver) which receives externalimage data De transmitted from the external device or the scanner dataDs transmitted from the image scanning device 200 as input image dataDi, the first process units 2Y, 2M, 2C and 2K which form a toner imagebased on the input image data Di on the sheet, the second process unit2V which forms a mark image of the luminescent toner on the sheet, and acontroller 120 which determines whether to make the second process unitform the mark image or not depending on the type of the source of thetransmission of the input image data Di. The controller 120 includes acentral processing unit (CPU), for example. Further, the controller 120may include a memory such as a random access memory (RAM) and a readonly memory (ROM).

The luminescent toner contains a luminescent material (e.g., afluorescent substance) that emits visible light when a light source(e.g., an atom of the luminescent material) transits from an excitedstate to a lower energy state (e.g., a lower excited state or the groundstate). The luminescent material transits from the lower energy state tothe excited state by receiving energy. For example, the luminescentmaterial transits from the ground state to the excited state byreceiving ultraviolet rays as the energy and returns to the ground stateby emitting visible light.

The external device is a facsimile machine, a personal computer (hostPC) or an information storage device (e.g. USB memory), for example.

The controller 120 includes, for example, a judgment section 121 (datatype judgment section) which judges the type of the transmission sourceof the input image data Di, a drive control section 123 (print operationcontroller) which drives each component of the image forming apparatus1, and a main control section 122. Further, the image forming device 100may include a status management section 130 (scanner unit statusmanagement section) for managing the operating status of the imagescanning device 200 and a storage unit 140 for storing superimpositioninformation (image superimposition setting) as information indicatingwhether or not the mark image should be printed by superimposing themark image on an image formation region (printable region on the sheet).

In the first embodiment, when the type of the transmission source is theimage scanning device 200, the controller 120 can make the secondprocess unit 2V form the mark image. The mark image formed in such casesincludes at least one of a letter (including a character), a figure suchas a circle and a triangle, a symbol (e.g. “COPY”), and a combination ofsome of them indicating that the transmission source is the imagescanning device 200.

In the first embodiment, when the type of the transmission source of theinput image data Di is an external device, the controller 120 can makethe second process unit 2V not form the mark image. However, thecontroller 120 may make the second process unit 2V form a mark imageindicating the type of the external device as the transmission source incases where the type of the transmission source is an external device.In cases where the external device is one of a facsimile machine, apersonal computer, and an information storage device, the mark imageformed by the second process unit can include at least one of theletter, the figure, the symbol (e.g., “FAX”, “PC”, “USB”, etc.), and acombination of some of them indicating one of the facsimile machine, thepersonal computer, and the information storage device as the type of thetransmission source.

The transmission/reception section 110 of the image forming device 100carries out the transmission/reception of print data as a request signalfor a print operation between itself and the external device (e.g., ahost computer 300 as a personal computer transmitting print informationor a facsimile machine (FAX) 400). Further, the transmission/receptionsection 110 of the image forming device 100 carries out thetransmission/reception of scan data (scanned data) between itself andthe scanner transmission/reception unit 203 of the image scanning device200.

The judgment section 121 judges the type of the transmission source ofthe input image data Di received from the transmission/reception section110.

The controller 120 controls each part of the image forming device 100.In order to control the print operation, the drive control section 123of the controller 120 controls parts such as the process units 2V, 2Y,2M, 2C and 2K, the primary transfer rollers 19V, 19Y, 19M, 19C and 19K,the secondary transfer roller 24 and the fixing unit 6. The statusmanagement section 130 of the image forming device 100 storesinformation indicating the operating status of the image scanning device200, that is, information indicating whether the image scanning device200 is in a driving state or on standby (a waiting state). The maincontrol section 122 issues commands to the drive control section 123 soas to switch the print speed based on the operating status of the imagescanning device 200.

Meanwhile, in the image scanning device 200, the scanner controller 202controls the scanner section 201 in order to perform a scanner scanningoperation, while controlling each part of the image scanning device 200.The operation panel 205 receives requests for the scanner scanningoperation and print (copy) commands based on operations by the operator.The scanner transmission/reception unit 203 as a scanning operationrequest reception unit transmits the print (copy) request received fromthe operation panel 205 to the transmission/reception section 110 of theimage forming device 100. Further, the scanner transmission/receptionunit 203 transmits various signals and the scan data (scanned data)received from the scanner section 201 via the scanner controller 202 toand receives them from the transmission/reception section 110 of theimage forming device 100. The scanner transmission/reception unit 203and the transmission/reception section 110 of the image forming device100 are capable of transmitting and receiving data with each other viawiring in the support members 101, for example. The status managementsection 204 of the image scanning device 200 stores informationindicating the operating status of the image forming device 100, thatis, information indicating whether the image forming device 100 is in adriving state or on standby (a waiting state). The scanner controller202 is capable of performing control so as to switch the scanning speedof the scanner section 201 based on the operating status of the imageforming device 100.

1-2 Luminescent Toner in Embodiment

The luminescent toner used in the second process unit 2V is produced bythe dissolution suspension method, for example. Binder resin in theluminescent toner is thermoplastic resin such as vinyl resin, polyamideresin, polyester resin and polyurethane resin.

Examples of a solvent usable as an organic solvent for dissolving thebinder resin in the production of the luminescent toner include, forinstance, (A1) hydrocarbon-based solvents such as ethyl acetate, xyleneand hexane, (A2) ester-based solvents such as methyl acetate, ethylacetate, butyl acetate and isopropyl acetate, (A3) ether-based solventssuch as diethyl ether, and (A4) ketone-based solvents such as acetone,methyl ethyl ketone, di-isobutyl ketone, cyclohexanone andmethylcyclohexane.

Examples of a parting agent in the luminescent toner include, forinstance, (B1) higher fatty acids and their metallic salts, (B2) fattyacid amides, (B3) ester waxes, and (B4) aliphatic hydrocarbon-basedwaxes such as paraffin/polyolefin-based waxes and their modifiedproducts.

Examples of inorganic powder used for the production of the luminescenttoner include, for instance, (C1) metallic oxides of metals such aszinc, aluminum, cerium, cobalt, iron, zirconium, chromium, manganese,strontium, tin and antimony, (C2) complex metallic oxides such ascalcium titanate, magnesium titanate and strontium titanate, (C3)metallic salts such as barium sulfate, calcium carbonate, magnesiumcarbonate and aluminum carbonate, (C4) clay minerals such as kaolin,(C5) phosphate compounds such as apatite, (C6) silicides such as silica,silicon carbide and silicon nitride, and (C7) carbon powder such ascarbon black and graphite.

A suspension stabilization agent used for the production of theluminescent toner is desired to be an agent that can be removed by useof acid having no affinity with the solvent since the toner particlesare granulated in the state of adhering to surfaces of particles afterbeing dispersed, for example. Desirable suspension stabilization agentsare, for example, calcium carbonate, calcium chloride, sodiumhydrocarbon, potassium hydrocarbon, hydroxyapatite, tricalciumphosphate, and the like.

Next, an example of the production in a case where the luminescent toneris fluorescent toner which emits light by being irradiated withultraviolet rays (UV toner) will be described below.

(E1) As the resin material, polyester resin having an acid value (theamount of potassium hydroxide in units of mg necessary for neutralizingfree fatty acid existing in 1 g of fat) of 2.9 mgKOH/g andweight-average molecular weight (in terms of styrene) in the vicinity of220000 (hereinafter referred to as “polyester resin material”) is used.(E2) As the parting agent, WEP-4 (produced by NOF Corporation) as esterwax is used.(E3) As a fluorescent substance, EXL-A830F (produced by Sinloihi Co.,Ltd.) is used. EXL-A830F has solubility of 10% or higher to ethylacetate. The color of fluorescence of EXL-A830F is blue.(E4) As charging control resin (CCR), Acrybase FCA-726 (produced byFujikura Kasei Co., Ltd.) is used.(E5) As the solvent, ethyl acetate is used.

A reason for selecting a substance soluble to ethyl acetate as thefluorescent substance is that a pigment dispersant used for the pigmentsof the common four colors (yellow, magenta, cyan, and black) adds itsown color to the printed image and the use of such a pigment dispersantshould be avoided in order to secure the transparency of the printedimage (the mark image printed with the luminescent toner). Anotherreason for selecting a substance soluble to ethyl acetate as thefluorescent substance is that a fluorescent substance as an ingredientinsoluble to ethyl acetate turns into toner and makes it impossible tosecure the transparency of the printed image in the printing.

In the toner of the common four colors (yellow, magenta, cyan, andblack), the pigment (color material) is added generally in an amount ofapproximately 5-10% with respect to the binder resin. Thus, if thefluorescent substance to be used is soluble to ethyl acetate at a ratioof 2.5% or higher, the fluorescent substance can be added in an amountof 10% or higher with respect to the binder resin (when the ratio of thebinder resin to ethyl acetate is 100 to 25). However, if the solubilityto ethyl acetate is 2.5%, for example, it is expected that precipitationof the fluorescent substance occurs in an ethyl acetate removal step inthe dissolution suspension method and the dispersion of the fluorescentsubstance and the securement of the transparency of the printed imagebecome difficult. Accordingly, the fluorescent substance to be used isdesired to be selected from fluorescent substances that are soluble toethyl acetate in an amount of 5% or higher in consideration of a reserveof solubility.

The composition of the liquid mixture of these materials (hereinafterreferred to as a “dispersed phase”) is as follows, for example:

E1: polyester resin material 145 pts.wt.E2: WEP-4 as the parting agent 7.8 pts.wt.E3: EXL-A830F as the fluorescent substance 0.6 pts.wt.-9.0 pts.wt.

(0.41%-6.21% with respect to the binder resin)

E4: FCA-726 as the charging control resin 0.22 pts.wt.E5: ethyl acetate as the solvent 600 pts.wt.

Incidentally, it is also possible to add materials other than thosedescribed above, such as a charging control agent and inorganic powder,as needed within an extent that they do not color the toner particles.The dispersed phase described above is heated and stirred at 50° C., forexample, until solid materials disappear.

On the other hand, the composition of a continuous phase is as follows,for example:

(Composition of Continuous Phase)

water 3000 pts.wt.

trisodium phosphate 12-hydrate 102 pts.wt.

The continuous phase described above was dissolved by mixing and heatingup to 60° C. and thereafter dilute nitric acid for pH control was added.Subsequently, aqueous solution of calcium chloride obtained bydissolving 49.2 pts.wt. of anhydrous calcium chloride in 500 pts.wt. ofpure water and heating up to 60° C. is added, and an aqueous medium(suspension stabilization agent solution) containing calcium phosphateis obtained by performing high-speed stirring at 10000 rpm for 5 minutesby using Neo Mixer (produced by Primix Corporation).

The aforementioned dispersed phase was mixed into this continuous phaseand granulation was conducted by further performing high-speed stirringat 8000 rpm for 30 seconds. Thereafter, ethyl acetate is removed bymeans of reduced-pressure distillation.

A base toner is obtained by cooling down the slurry, conducting acidwashing and dehydration to remove the suspension stabilization agent,conducting aqueous rinsing, and thereafter conducting dehydration anddrying. In the acid washing and the aqueous rinsing, no desorption orelution of the fluorescent substance was observed.

An external additive toner was produced by adding 1.0 pts.wt. ofhydrophobic silica R-8200 (produced by Nippon Aerosil Co., Ltd., averageprimary particle diameter: 12 nm) to 100 pts.wt. of the base toner andmixing them together by using Hensel Mixer (produced by Mitsui MiningCompany Limited).

It is also possible to produce the UV toner while changing the type ofthe fluorescent substance to EXL-A831F (produced by Sinloihi Co., Ltd.,solubility to ethyl acetate: 10% or higher, luminescent color: green).In this case, the amount of the fluorescent substance is desired to bewithin a range from 0.41% to 8.28% with respect to the binder resin.

It is also possible to produce the UV toner while changing the type ofthe fluorescent substance to SOM-5-0114 (Orient Chemical Industries Co.,Ltd., solubility to ethyl acetate: 10% or higher, luminescent color:red). In this case, the amount of the fluorescent substance is desiredto be within a range from 0.41% to 2.07% with respect to the binderresin.

<<1-3>> Operation of Embodiment

FIG. 3 is a flowchart showing an example of the operation of the imageforming device 100 of the image forming apparatus 1 according to thefirst embodiment. First, the judgment section 121 of the controller 120judges whether or not the input image data (received data) Di receivedby the transmission/reception section 110 is scanner data Ds whosetransmission source is the image scanning device 200 (step S1).Specifically, the judgment section 121 judges whether the input imagedata Di is scanner data Ds or external image data De whose transmissionsource is an external device.

When the input image data Di is judged to be scanner data Ds in the stepS1, the main control section 122 of the controller 120 receives thescanner data Ds (step S2).

Subsequently, the main control section 122 of the controller 120 refersto a table 141 regarding the image superimposition setting (setting inregard to the mark image of the luminescent toner) stored in the storageunit 140 (step S3).

FIG. 4 is a diagram showing an example of the table 141. The table 141is set in the storage unit 140 according to operations on the operationpanel 205, for example. The table 141 includes a mark image “ON” settingas a setting for printing the mark image of the luminescent toner on thesheet, a mark image “OPTION” setting as a setting for making a displayfor asking the user whether or not to print the mark image of theluminescent toner on the sheet, and a mark image “OFF” setting as asetting for not printing the mark image of the luminescent toner on thesheet.

Subsequently, the main control section 122 of the controller 120 judgeswhether to perform the printing of the mark image of the luminescenttoner (referred to also as a “spot color print operation”) or not (stepS4). When the image superimposition setting is the mark image “ON”setting, the judgment in the step S4 is YES and the main control section122 of the controller 120 controls the drive control section 123 so asto perform the printing with normal toner on the basis of the scannerdata Ds while controlling the drive control section 123 so as to printthe mark image of the luminescent toner (step S5). The normal toner inthe present application means toner used in the image forming device 100other than the luminescent toner, such as the yellow toner, the magentatoner, the cyan toner and the black toner.

When the input image data Di is judged not to be scanner data Ds in thestep S1 (NO in the step S1), the main control section 122 of thecontroller 120 receives external image data De whose transmission sourceis an external device different from the image scanning device 200 (e.g.print data whose transmission source is a host PC, FAX data whosetransmission source is a facsimile machine, or print data whosetransmission source is an external information storage device) (stepS6).

When the judgment in the step S4 is NO or after the step S6, the maincontrol section 122 of the controller 120 controls the drive controlsection 123 so as to perform the printing with the normal toner on thebasis of the input image data Di without carrying out the printing ofthe mark image of the luminescent toner (step S7).

FIG. 5 is a diagram showing an example of a composite image (image 73)of an image 71 formed with the normal toner and an image 72 formed withthe luminescent toner (mark image). The image 71 is an image obtained byhaving the image scanning device 200 optically scan the image of thedocument. The image 72 is the mark image based on template dataprestored in the storage unit 140. The image 73 is the image printed onthe sheet, that is, the composite image of the image 71 and the image72.

The image 73 includes a color image 71 a printed in a normal printoperation by using the normal toner (e.g., the image of a building inthe image 73) and an image 72 a as the mark image printed in the spotcolor print operation by using the luminescent toner (e.g., the letters“COPY” in the image 73). It is desirable that the mark image of theluminescent toner (image 72 a) be formed as an upper layer on the image71 a of the normal toner. In cases where a UV toner is used as theluminescent toner, the mark image (image 72 a) formed on the sheet istransparent under visible light (in a state of being illuminated withvisible light), and becomes visible as in the image 73 in FIG. 5 whenirradiated with ultraviolet rays, for example.

In the image 73, the template data image like “COPY” as the image 72 aprinted as the mark image is a UV toner image, for example. Since the UVtoner image is transparent when no ultraviolet rays are applied thereto,the user generally cannot visually recognize the template data image(mark image) under visible light. However, irradiating the template dataimage with ultraviolet rays from a black light or the like causes thetemplate data image to emit visible light (e.g., the letters “COPY”emitting light), which allows the user to visually recognize thetemplate data image.

<<1-4>> Effects of Embodiment

As described above, with the image forming apparatus 1 according to thefirst embodiment, when a mark image formed with luminescent toner (e.g.,UV toner) is printed on a recording medium, the type of the transmissionsource of the image printed on the recording medium (i.e., the image inwhich the image 71 has been formed with the normal toner) can beidentified.

Further, when the copy function of the image forming apparatus 1 (makinga copy) is used, the image 71 of the normal toner is formed on therecording medium on the basis of the image scanned by the image scanningdevice 200 (image of the original) while printing the mark image such as“COPY” on the image 71 formed on the recording medium, which clearlyindicates that the printed sheet on the stacker 28 is printed matter(copy) ejected from the image forming apparatus 1 (specifically, theimage forming device 100). Therefore, it is possible to distinguishprinted matter (copy) obtained by copying the original and the original.

Furthermore, since the mark image superimposed on the image 71 of thenormal toner is printed by using UV toner, satisfactory print quality(copy quality) of the printed matter (copy) with the mark imagesuperimposed thereon can be secured without hindering the image formingoperation using the normal toner.

Moreover, the mark image can be formed as a template in a fixed formirrespective of the type of the image scanned by the image scanningdevice 200.

When the images are formed with the toner, the images (i.e., tonerimages) of respective colors are stacked from a bottom layer to a toplayer on the recording medium. In this case, visibility of the tonerimage of the top layer is better than that of the toner image of thebottom layer. Thus the mark image (luminescent image formed with theluminescent developer) may be formed as the top layer of the toner imagelayer (toner layer) on the recording medium in order to improve thevisibility of the mark image, for example. When the color image (i.e.,the toner image formed with the normal toner) is intended to emphasizerather than the mark image, the mark image is formed as the bottomlayer. In this way the desired image can be obtained by changing theorder of forming the images (including the image formed with the normaltoner and the image formed with the luminescent toner) according to theimage (toner image) intended to emphasize on the recording medium.

In the present embodiment, the example of forming the color image withthe normal toner and the mark image with the luminescent toner by theimage forming apparatus 1 as an electrophotographic system device isdescribed. However, the present embodiment is not limited to the exampledescribed above. The color image formed with the normal toner and themark image formed with the luminescent toner may be formed by using aninkjet system device such as an inkjet printer, for example. In thiscase, an ink image can be formed on the recording medium by a head forinkjet system (inkjet head) as mechanism for forming the image on therecording medium, for example. In this case, the ink image may be formedby using the inkjet head instead of the process unit as the imageforming unit which forms the image. When the color image is formed bythe inkjet system device, the color image is can be formed by usingnormal color ink such as yellow ink, magenta ink, cyan ink, and blackink. Further, the luminescent material can be used to form the markimage instead of pigment and dye used for normal color ink when thecolor image is formed by the inkjet system device. In the presentembodiment, the example of forming the toner image as developer imageformed on the recording medium is described. However, the ink image asthe developer image may be formed on the recording medium instead of thetoner image.

<<2>> Second Embodiment

An image forming apparatus according to a second embodiment of thepresent invention differs from the image forming apparatus according tothe first embodiment in the processing performed by the controller 120of the image forming device 100. In the other features, the imageforming apparatus of the second embodiment is equivalent to the imageforming apparatus of the first embodiment. Thus, the followingdescription of the second embodiment will be given referring also toFIGS. 1 and 2.

FIG. 6 is a flowchart showing an example of the operation of the imageforming device 100 of the image forming apparatus according to thesecond embodiment. First, the judgment section 121 of the controller 120judges the transmission source of the input image data (received data)Di received by the transmission/reception section 110 (step S11). Forexample, in the second embodiment, the judgment section 121 judgeswhether the transmission source is the image scanning device 200(scanner), a host PC or a facsimile machine. However, the types of thetransmission source are not limited to the examples described in thesecond embodiment.

When the transmission source is judged to be the scanner in the step S11(step S11: SCANNER), the main control section 122 of the controller 120receives scanner data Da (step S21).

Subsequently, the main control section 122 of the controller 120 refersto the table 141 regarding the image superimposition setting (setting inregard to the mark image of the luminescent toner) stored in the storageunit 140 (step S22).

Subsequently, the main control section 122 of the controller 120 judgeswhether to perform the spot color print operation or not (step S23).When the image superimposition setting is the mark image “ON” setting,the judgment in the step S23 is YES and the main control section 122 ofthe controller 120 controls the drive control section 123 so as toperform the printing by use of the normal toner on the basis of thescanner data Ds while controlling the drive control section 123 so as toprint the mark image with the luminescent toner (step S51).

When the transmission source is the scanner, as shown in FIG. 5, themain control section 122 of the controller 120 selects a template dataimage for cases where the transmission source is the scanner(hereinafter referred to also as a “scanner-dedicated mark image”) asthe mark image from a plurality of template data images stored in thestorage unit 140 and prints the scanner-dedicated mark image (step S51).For example, when the transmission source is the scanner, the maincontrol section 122 of the controller 120 selects the image 72 a as themark image and prints the image 72 a on the sheet as shown in FIG. 5.

When the transmission source is judged to be a host PC in the step S11(step S11: PC), the main control section 122 of the controller 120receives external image data De whose transmission source is the host PC(step S31).

Subsequently, the main control section 122 of the controller 120 refersto the table 141 regarding the image superimposition setting (setting inregard to the mark image of the luminescent toner) stored in the storageunit 140 (step S32).

Subsequently, the main control section 122 of the controller 120 judgeswhether to perform the spot color print operation or not (step S33).When the image superimposition setting is the mark image “ON” setting,the judgment in the step S33 is YES and the main control section 122 ofthe controller 120 controls the drive control section 123 so as toperform the printing by use of the normal toner on the basis of thereceived print data while controlling the drive control section 123 soas to print the mark image with the luminescent toner (step S51).

FIGS. 7A and 7B are diagrams each showing an example of the mark imageof the luminescent toner printed in a printable region P1 of the sheet.The printable region P1 is a region on the sheet in which at least thefirst process units 2Y, 2M, 2C and 2K form a toner image. The mark image(image 81) in FIG. 7A illustrates an example of the mark image used whenthe transmission source is a host PC. The mark image (image 82) in FIG.7B illustrates an example of the mark image used when the transmissionsource is a facsimile machine. In cases where UV toner is used as theluminescent toner, the mark image (image 81, 82) formed on the sheet istransparent under visible light, and becomes visible as shown in FIGS.7A and 7B when irradiated with ultraviolet rays, for example.

FIGS. 8A and 8B are diagrams each showing an example of the mark imageof the luminescent toner printed in a marginal region (region P2) of thesheet other than the printable region P1. The mark image (image 81) inFIG. 8A illustrates an example of the mark image used when thetransmission source is a host PC. The mark image (image 82) in FIG. 8Billustrates an example of the mark image used when the transmissionsource is a facsimile machine. In cases where UV toner is used as theluminescent toner, the mark image (image 81, 82) formed on the sheet istransparent under visible light, and becomes visible as shown in FIGS.8A and 8B when irradiated with ultraviolet rays, for example.

When the transmission source is a host PC, the main control section 122of the controller 120 selects a template data image for cases where thetransmission source is a host PC (hereinafter referred to also as a“host PC-dedicated mark image”) as the mark image from a plurality oftemplate data images stored in the storage unit 140 and prints the hostPC-dedicated mark image (step S51). For example, when the transmissionsource is a host PC, the main control section 122 of the controller 120selects the image 81 as the mark image and prints the image 81 in theprintable region P1 of the sheet as shown in FIG. 7A. As shown in FIG.8A, it is also possible to form the mark image in the marginal region(region P2) of the sheet other than the printable region P1.Incidentally, there are no limitations on the number and positions ofmark images printed.

When the transmission source is judged to be a facsimile machine in thestep S11 (step S11: FAX), the main control section 122 of the controller120 receives external image data De whose transmission source is thefacsimile machine (step S41).

Subsequently, the main control section 122 of the controller 120 refersto the table 141 regarding the image superimposition setting (setting inregard to the mark image of the luminescent toner) stored in the storageunit 140 (step S42).

Subsequently, the main control section 122 of the controller 120 judgeswhether to perform the spot color print operation or not (step S43).When the image superimposition setting is the mark image “ON” setting,the judgment in the step S43 is YES and the main control section 122 ofthe controller 120 controls the drive control section 123 so as toperform the printing by use of the normal toner on the basis of thereceived FAX data while controlling the drive control section 123 so asto print the mark image with the luminescent toner (step S51).

When the transmission source is a facsimile machine, the main controlsection 122 of the controller 120 selects a template data image forcases where the transmission source is a facsimile machine (hereinafterreferred to also as a “facsimile-dedicated mark image”) as the markimage from a plurality of template data images stored in the storageunit 140 and prints the facsimile-dedicated mark image (step S51). Forexample, when the transmission source is a facsimile machine, the maincontrol section 122 of the controller 120 selects the image 82 as themark image and prints the image 82 in the printable region P1 of thesheet as shown in FIG. 7B. As shown in FIG. 8B, it is also possible toprint the mark image in the margin (region P2) of the sheet other thanthe printable region P1. Incidentally, there are no limitations on thenumber and positions of mark images printed.

When the judgment in the step S23, S33 or S43 is NO, the main controlsection 122 of the controller 120 controls the drive control section 123so as to perform the printing by use of the normal toner (normal printoperation) without performing the printing of the mark image of theluminescent toner (step S52).

As described above, in the image forming apparatus according to thesecond embodiment, the main control section 122 of the controller 120 iscapable of determining whether to print the mark image of theluminescent toner or not depending on the type of the transmissionsource.

In cases where the mark image is printed, the main control section 122of the controller 120 prints the mark image by selecting a template dataimage depending on the type of the transmission source, which makes itpossible to distinguish whether the printed sheet ejected from the imageforming apparatus (specifically, the image forming device 100) isprinted matter (copy) obtained by the copy function, printed matterobtained by the print function (printing based on a command from a hostPC), or printed matter obtained by the FAX function. In other words, thetype of the transmission source of the image printed on the recordingmedium (i.e., the image in which the image 71 has been formed with thenormal toner) can be identified.

Especially in cases where the transmission source is the scanner amongthe multiple types of transmission sources (i.e., in cases of performingthe printing by the copy function), the printing of the mark image byuse of the luminescent toner makes it possible to distinguish whether aprinted sheet left behind in the vicinity of the image forming apparatus(e.g., the image scanning device 200, the stacker 28, etc.) is theoriginal or a copy.

What is claimed is:
 1. An image forming apparatus comprising: an imageforming device which forms an image on a recording medium; and an imagescanning device which transmits scanned image data generated byoptically scanning an image to the image forming device; wherein: theimage forming device includes: a receiver which receives at least one ofexternal image data transmitted from an external device and the scannedimage data transmitted from the image scanning device as input imagedata; a first image forming unit which forms a developer image based onthe input image data on the recording medium; a second image formingunit which forms a mark image on the recording medium with luminescentdeveloper containing a luminescent material, the luminescent materialemitting visible light; and a controller which determines whether tomake the second image forming unit form the mark image or not dependingon a type of a transmission source of the input image data.
 2. The imageforming apparatus according to claim 1, wherein the luminescent materialtransits from ground state to an excited state by receiving energy. 3.The image forming apparatus according to claim 1, wherein theluminescent material transits from ground state to an excited state byreceiving ultraviolet rays.
 4. The image forming apparatus according toclaim 1, wherein the controller makes the second image forming unit formthe mark image when the type of the transmission source is the imagescanning device.
 5. The image forming apparatus according to claim 4,wherein the mark image formed by the second image forming unit when thetype of the transmission source is the image scanning device includes atleast one of a letter, a figure, and a symbol indicating that thetransmission source is the image scanning device.
 6. The image formingapparatus according to claim 1, wherein the controller does not make thesecond image forming unit form the mark image when the type of thetransmission source is the external device.
 7. The image formingapparatus according to claim 1, wherein when the type of thetransmission source is the external device, the controller makes thesecond image forming unit form the mark image indicating the type of theexternal device as the transmission source.
 8. The image formingapparatus according to claim 7, wherein: the external device is one of afacsimile machine, a personal computer, and an information storagedevice, and the mark image formed by the second image forming unit whenthe type of the transmission source is the external device includes atleast one of a letter, a figure, and a symbol indicating one of thefacsimile machine, the personal computer, and the information storagedevice as the type of the transmission source.
 9. The image formingapparatus according to claim 1, wherein the second image forming unitforms the mark image in a printable region on the recording medium inwhich the first image forming unit forms the developer image.
 10. Theimage forming apparatus according to claim 1, wherein the second imageforming unit forms the mark image in a marginal region on the recordingmedium other than a printable region in which the first image formingunit forms the developer image.
 11. The image forming apparatusaccording to claim 1, wherein on the recording medium, the mark imageformed by the second image forming unit is formed as an upper layer onthe developer image formed by the first image forming unit.
 12. Theimage forming apparatus according to claim 1, wherein the mark image istransparent under visible light and is visually recognizable whenirradiated with ultraviolet rays.
 13. The image forming apparatusaccording to claim 1, wherein the luminescent developer is fluorescenttoner which emits light by being irradiated with ultraviolet rays. 14.The image forming apparatus according to claim 1, wherein the developerimage based on the input image data is formed with toner.